class_docstr: Constructs cell dataset
class_docstr_tok: ["Constructs","cell","dataset"]
code: def __len__(self):
      return len(self.sample_dirs)
  
file_path: skorch/examples/nuclei_image_segmentation/dataset.py
imports: from itertools import zip_longest, product, chain
  import random
  import numpy
  import torch
  from torch.utils.data import Dataset
  from torchvision.transforms.functional import pad, to_tensor, normalize, hflip, vflip, crop
  from PIL import Image
label_desc: Use image node_id 2 for calling the CellsDataset obj's underlying member method code with example usage: obj.__len__() and returns: len